The present invention relates to a liquid receiver used in a car air conditioner which is a refrigeration cycle mounted on, for example, an automobile. The liquid receiver separates gas-liquid-mixed-phase refrigerant into gas-phase refrigerant and liquid-phase refrigerant. The present invention also relates to a condenser in which such a liquid receiver is used.
Herein, the term “liquid-phase refrigerant” encompasses liquid-phase predominant mixed-phase refrigerant containing a small amount of gas-phase refrigerant.
There has been known a condenser of a car air conditioner which includes a condensation section, a supercooling section provided below the condensation section, and a liquid receiver provided between the condensation section and the supercooling section. The liquid receiver is composed of a tubular body whose longitudinal direction coincides with the vertical direction and which is closed at the upper and lower ends thereof. Refrigerant flowing out of the condensation section flows into the supercooling section through the liquid receiver. Specifically, gas-liquid-mixed-phase refrigerant flowing out of the condensation section into the liquid receiver is separated into gas-phase refrigerant and liquid-phase refrigerant in the liquid receiver, and the liquid-phase refrigerant flows into the supercooling section.
A liquid receiver for use in a condenser of the above-described type has been proposed (see Japanese Patent Application Laid-Open (kokai) No. 2015-28394). The proposed liquid receiver includes a tubular female screw forming portion whose axial direction coincides with the vertical direction and which has a female screw formed on an upper portion of the inner circumferential surface thereof; a tubular body portion whose lower end portion is joined to the female screw forming portion such that the longitudinal direction of the body portion coincides with the vertical direction and which is closed at the upper end and is open at the lower end; and a columnar cap which is inserted into the female screw forming portion, which has a male screw for threading engagement with the female screw. The female screw forming portion has an insertion portion which is inserted into the body portion and is joined to the inner circumferential surface of the body portion and an uninserted portion disposed outside the body portion. The female screw is provided on the uninserted portion, the body portion has a refrigerant inflow hole through which refrigerant flows from the condensation section of the condenser into the body portion, and the female screw forming portion has a refrigerant outflow hole through which refrigerant flows out to the supercooling section of the condenser. A seal means is provided so as to establish sealing between a region of the inner circumferential surface of the female screw forming portion, which region is located below the female screw, and a region of the outer circumferential surface of the cap, which region is located below the male screw.
However, the liquid receiver disclosed in the publication has the following problem. Specifically, the refrigerant inflow hole through which refrigerant flows from the condensation section of the condenser into the body portion is formed in the body portion, and the refrigerant outflow hole through which refrigerant flows out to the supercooling section of the condenser is formed in the female screw forming portion, so that the distance in the vertical direction from the lower end of the liquid receiver to the upper end of the refrigerant inflow hole is relatively long. Therefore, when a refrigerating cycle which includes a condenser having such a liquid receiver is charged with refrigerant, a relatively long time is needed to fill a portion of the internal space of the liquid receiver located below the refrigerant inflow hole with liquid-phase refrigerant. In addition, in the case where the amount of refrigerant charge is constant, the width of a stable range within which the degree of supercooling becomes constant becomes relatively narrow.